Field of the Invention
The embodiments of the present disclosure relate to an organic light-emitting display (OLED) device, and more particularly to an OLED device capable of suppressing a particle cover layer from being excessively spread.
Description of the Related Art
As the era of information technology has unfolded, the field of display devices has been growing rapidly, as information can be represented in electrical signals in the form of visual images. In accordance with this, research is ongoing for various flat panel display devices to make them thinner, lighter and capable of consuming less power. Flat panel display devices include a liquid crystal display (LCD) device, a plasma display panel (PDP) device, a field emission display (FED) device, an electro-wetting display (EWD) device, and an organic light emitting display (OLED) device, etc.
Among others, an OLED device is capable of producing light on its own, and thus, does not require an additional light source, unlike an LCD. Therefore, an OLED device can be made lighter and thinner. Further, an OLED device has advantages in that it is driven with low voltage to consume less power, and it has fast response time, wide viewing angle and infinite contrast ratio (CR). For these reasons, an OLED device is acknowledged as the next generation display device. However, an OLED device is especially vulnerable to moisture and oxygen permeation, making it is less reliable than other flat panel display devices.
An OLED device displays images using an organic light-emitting element which is self-luminous. An OLED device includes a plurality of pixels, each of which includes an organic light-emitting element. An organic light-emitting element includes a first electrode and second electrode facing each other. The organic light-emitting element further includes a light-emitting layer disposed between the first electrode and the second electrode, and is made of an organic substance and creates electroluminescence.
For a top emission OLED device, a first electrode is transparent or transflective (semi-transparent) while a second electrode is reflective, so that light generated from an organic light-emitting layer is emitted upwardly through the first electrode. Additionally, in order to ensure the reliability of an OLED device, a transparent, encapsulation unit is formed on the organic light-emitting element to protect the organic light-emitting element from oxygen and moisture. Previously in a top emission OLED device, a glass encapsulation unit was employed as the encapsulation unit.